Beyond 650 V Dynamic Switching of High Voltage AlGaN/GaN/AlN HEMTs on Monocrystalline AlN Substrates

We present AlN-based GaN-channel HEMTs with an undoped AlN-buffer layer, MOCVD-grown on a 1" PVT-grown monocrystalline AIN substrate for high-voltage switching applications. These devices achieve switching transients of 1A/766V on 9.2 mm transistors and 5A/250V switching on 92 mm transistors, with an on-state resistance of 115mΩ and a saturation current exceeding 50 A. 1530 V breakdown voltage and a power density of 1.2GW/cm2 were achieved on test transistors with 18.25μm gate-drain separation. The study further evaluates the impact of GaN channel thickness on dynamic Ron degradation under high voltage stress and highlights the role of the AlN-buffer/GaNchannel interface quality on the dispersion effects. The presented switching voltage and current levels as well as the power density are the highest achieved on monocrystalline AIN substrates so far.